Christensen Darren R, Grace Randolph C
University of Arkansas for Medical Sciences, USA.
Behav Processes. 2009 Jun;81(2):233-7. doi: 10.1016/j.beproc.2009.01.006. Epub 2009 Jan 31.
Four pigeons were exposed to a concurrent-chains procedure in which the initial link was constant (variable-interval 10s) while the terminal-link delays changed across sessions according to a pseudorandom binary series. In the short condition, the left terminal link was a fixed-interval 8s and the right terminal link was either fixed-interval 4s or fixed-interval 16s; in the long condition, the left terminal link was fixed-interval 16s and the right terminal link was either fixed-interval 8s or fixed-interval 32s. Multiple regression showed that response allocation was sensitive to the current session immediacy ratio, with greater sensitivity in the long than the short condition. This replicates the terminal-link effect [MacEwen, D., 1972. The effects of terminal-link fixed-interval and variable-interval schedules on responding under concurrent-chained schedules. J. Exp. Anal. Behav. 18, 253-261] in a pseudorandom binary series design. Grace and McLean's [Grace, R.C., McLean, A., 2006. Rapid acquisition in concurrent chains: evidence for a decision model. J. Exp. Anal. Behav. 85, 181-202] decision model provided a good description of the data and predicted the terminal-link effect. Estimates of the criterion parameter increased in the long condition but less than proportionally, and were close to the expected values based on the programmed schedule durations, as predicted by the decision model. These results provide additional support for the decision model as an account of choice in concurrent chains.
四只鸽子接受了一种并发链程序，其中初始链是恒定的（可变间隔10秒），而终端链延迟根据伪随机二进制序列在各实验环节中变化。在短条件下，左终端链是固定间隔8秒，右终端链是固定间隔4秒或固定间隔16秒；在长条件下，左终端链是固定间隔16秒，右终端链是固定间隔8秒或固定间隔32秒。多元回归表明，反应分配对当前实验环节的即时性比率敏感，长条件下的敏感性高于短条件。这在伪随机二进制序列设计中复制了终端链效应[MacEwen, D., 1972. 终端链固定间隔和可变间隔时间表对并发链时间表下反应的影响。《实验行为分析杂志》18, 253 - 261]。Grace和McLean的[Grace, R.C., McLean, A., 2006. 并发链中的快速习得：决策模型的证据。《实验行为分析杂志》85, 181 - 202]决策模型对数据提供了很好的描述，并预测了终端链效应。标准参数的估计值在长条件下增加，但增加幅度小于比例关系，并且接近基于编程时间表持续时间的预期值，正如决策模型所预测的那样。这些结果为决策模型作为并发链中选择行为的一种解释提供了额外支持。
